Compensating reheater and superheater



Sept. 8, 1936. c. w. GORDON 2,053,429

' COMPENSATING REHEATER AND SUPERHEATER I Filed Sept. 8, 1934 INVENTOR ICH/l/flf' 144 60,600

ATTORN EY Patented Sept. 8, 1936 UNITED STATES PATENT OFFICECOIWPENSATING REHEATER AND SUPERHEATER Application September 8, 1934,Serial No. 743,175

2 Claims.

My invention relates to superheating steam and aims to provide anarrangement whereby the temperature of the steam may be readily andaccurately controlled.

superheated steam is used in practically all steam turbines, but in mostturbine installations the steam is reheated between certain expansionstages so that a reheater is employed as Well as a superheater. In suchinstallations, there is a natural tendency for the temperature of thesuperheated steam of the reheated steam to vary with the load. For bestefficiency of the turbine, however, such temperatures should bemaintained constant at or near the prescribed maximum.

It is an object of my invention to provide an arrangement whereby suchvariations are minimized.

In accordance with my invention, the superheating surface and thereheating surface is divided into two unequal sections, each one arranged in a different gas path, and the percentage flow of gases in thedifferent gas paths is regulated to maintain the superheat and/or reheattemperature as nearly at the desired constant temperature as may be.

In order that my invention, together with its objects and advantages,may be fully and readily understood, I will now describe in detail aboiler having a superheater and a reheater, an exemplification of myinvention which is illustrated in the accompanying drawing and which hasbeen selected by way of example from a number of possible embodimentsthereof. In the drawing,

The figure is a vertical sectional view of an installation in accordancewith the invention.

In the arrangement illustrated, Ill is a boiler of a conventional typehaving a furnace chamber l2, a slag screen bank l4 immediately abovesaid furnace chamber, and a main bank of generating tubes l6 above andspaced from said bank [4. The chamber l8 lies between banks I4 and I6and the superheater 20 preferably is placed in such chamber. The gastouched surface of the superheater 20 is composed of a number of unitsone of which appears at 22, and each such unit is divided into twosections 24 and 26 in such manner that the heating surface of onesection is very considerably greater than that of the other.Furthermore, bafiling means 28 is provided forming two gas paths 30 and32 so arranged that section 24 lies in one path 30 and section 26 liesin the other path 32, the bafile 28 extending between the two sections.In the arrangement illustrated, the bafiling 28 extends continuouslyfrom the upper edge of the slag screen bank l4 vertically upward throughthe bank l6 and laterally to one edge of the boiler setting, where thegas is discharged into a flue 34. At the inlet of the flue 34, twoindependently hand controlled dampers 36 and 38 are placed so that thepercentage flow of gases in the paths 30 and 32 can be regulated at willwithin wide limits. However, it is obvious that dampers 36 and 38 can beautomatically controlled if so desired. By throwing more of the gasesover the larger section 24, the temperature of the steam delivered bysuperheater 2!) can be increased beyond that normally expected at agiven load and this fact is taken advantage of to maintain the steamtemperature delivered by the boiler to an operation at as nearly theprescribed maximum as possible. Also, in the arrangement illustrated, areheater 4B is placed in the flue 34. Reheater 40 is composed of anumber of units one of which is illustrated at 42. The gas touchedsurface of each of units 42 is divided into two sections 44, 46, onehaving materially more active surface than the other and a bafile wall48 joining with baffle wall 28 extends between the sections 44 and 46 soas to divide the flue 34 into two gas paths 50 and 52 which extendlongitudinally of flue 34 at least as far as the units 46.

Furthermore, a different division may be made of the heating surface inthe superheater 20 as compared to that in reheater 40. This is indicatedin the drawing by the fact that in heater 20 there are two and a halfloops per unit in path 30 to one and a half loops per unit in path 32, aratio of 1.6 while in heater 4!) there are two loops per unit in path 59to one loop per unit in path 52, a ratio of two. Each of the two heatersis thereby enabled to approach the optimum steam temperature undervarying loads.

What I claim is:

1. The combination of a boiler having a reheater and superheater andhaving two entirely separate gas paths in which said superheater andreheater lie, said superheater and reheater each having sections in bothpaths but each having its surface unequally divided between said pathsand having its larger section in a given path, and means whereby thepercentage flow of gases through said paths may be varied to regulatethe final temperature of steam from said superheater and reheater.

2. The combination as set forth in claim 1 and in which the ratio of thesuperheater surface in a given gas path to that in the other gas path isdifferent from the ratio of the reheater surface in said given path tothat in said other path.

CHARLES W. GORDON.

